This invention relates generally to a method of assuring safe driving, and particularly to a method of detecting a vehicle driver's alertness to drive safely and to alarm the driver when his alertness falls below a preselected level.
Heretofore, several methods have been proposed for preventing dangerous driving due to a driver's low alertness resulting from, for example, overfatigue, dozing or intoxication by drugs such as alcohol. One conventional method is to require the vehicle driver to respond to external stimuli in order to check the degree of his alertness. Another one is carried out by examining the driver's physical condition by, for example, observing the driver's eyeball movement which is sensed by a suitable sensing means attached to the driver's head.
However, several defects are encountered in the above-mentioned prior art as discussed below. That is, these methods are not practically suitable in that the detection of the driver's low alertness is comparatively slow and often erroneous, and furthermore it is very cumbersome to the driver to drive with the eyeball movement sensing means.